KABUL, June 15 -- Gen. Stanley A. McChrystal, who took over Monday as the top commander in Afghanistan, said he will launch a broad assessment of how U.S. and NATO troops are arrayed in the country to ensure his forces are focused on safeguarding key population centers and not hunting down Taliban fighters.

"We are going to look at those parts of the country that are most important -- and those typically, in an insurgency, are the population centers," McChrystal said in an interview shortly after pinning on his fourth star. He replaced Gen. David D. McKiernan, who was fired by Defense Secretary Robert M. Gates after 11 months on the job.

McChrystal's comments suggested that he wanted to pull forces out of some of the more remote, mountainous areas of Afghanistan where few people live and where insurgent fighters may be seeking refuge. In recent months these isolated pockets have been the scene of some of the most intense fighting between U.S. troops and insurgents.

The debate over whether to use U.S. troops to hunt down the enemy in the remote mountains or employ them in cities and villages to protect the population against Taliban intimidation and attacks has dogged U.S. commanders since the beginning of the Afghan war in 2001. Some senior military commanders have argued that the U.S. has never committed enough troops to the country to execute a classic counterinsurgency strategy focused on safeguarding the Afghan people.

"We've got to ruthlessly prioritize, because we don't have enough forces to do everything, everywhere," McChrystal said. He added that he would be especially reluctant to commit his forces to rugged areas where it would be difficult to extend the reach of the Afghan government or spur economic development. "If you are not prepared to come in with a reasonable level of governance and a reasonable level of development, then just going in to hold [the ground] doesn't have a strong rationale," he said.

One area that is likely to receive scrutiny from the new commander is the Korengal Valley in eastern Afghanistan, where U.S. troops have for several years been locked in an intense battle that has produced more American casualties than just about any region of the country.

Senior U.S. officials in eastern Afghanistan say most of the hard-core insurgents battling American troops there are Korengalis who receive weapons, training and money from al-Qaeda and Taliban facilitators, crossing the porous border from Pakistan. In recent months, U.S. commanders have debated whether to increase the American force in the Korengal Valley in an effort to rout the insurgents, or simply leave the isolated area. A third option is to hold force levels in the area steady.

"We are having huge discussions about it," said Col. John Spiszer, who has commanded U.S. troops in the region that includes the Korengal for 12 months. One theory put forward by some American military officials holds that keeping the enemy fighters tied down, battling U.S. troops in the remote valley, makes it harder for the insurgents to attack in other areas that are more amenable to economic development and progress. "I know there is a certain amount of truth to that," Spiszer said. "But is it enough to justify the cost? I think about it all the time."

In areas such as the Korengal, characterized by steep mountains and narrow valleys, insurgents tend to have an advantage over U.S. forces, who are weighed down by body armor and are not as familiar with the territory. American armored vehicles and surveillance planes are also far less effective in mountainous terrain. Some of the heaviest losses suffered by Soviet troops in the 1980s came in the remote mountain passes along the Afghan-Pakistani border.

"The question in the Korengal is: How many of those fighters, if left alone, would ever come out of there to fight?" McChrystal said. "I can't answer it. But I do sense that you create a lot of opposition through operations" by the military. "So you have got to decide where you are going to operate."

He said he plans to spend eight to 10 days meeting with his military commanders as well as some provincial and village leaders. McChrystal said the core of his review will focus on which areas the U.S., NATO and Afghan troops could secure with the current force levels.

In judging the effect his strategy was having on security, McChrystal said he will avoid such measurements as the number of insurgent attacks, enemies killed or raids initiated by U.S. forces. Instead he pledges to focus on indicators that shed light on local governance and economic development.

"One indicator might be how well commerce is moving," McChrystal said. "If an individual can move his product to market right away from his village or town, that is telling. If he's got to go through six checkpoints and pay a bribe at each one, that is a sign that you've got abuse of governance or an insurgency, depending on who's doing it."

He said he will also inquire regularly whether local government officials feel comfortable enough to live with their families in the areas they are serving. In places such as restive Konar province in the east and Taliban-controlled Zabol province in the south, most government officials move their wives and children to safer areas of the country.

"Do they feel comfortable enough to visit their constituents without a security presence?" he asked, citing another potential measure.

The general also said he wants to revamp the way U.S. forces investigate and respond to civilian casualties, which have produced a tremendous amount of resentment and anger throughout the country. He said he might assemble a team that would fly to an area on only a few hours' notice to investigate allegations of civilian deaths. And he pledged that the United States will try to be more culturally sensitive in how it responded to mistakes.

"The Afghan people, particularly the Pashtuns, have a sense of honor and equity that says if you commit a wrong that it has got to be adjudicated, and the person who commits that wrong has got to make some sort of compensation," McChrystal said. "We have to understand that process so that when we engage with the population, we don't make things worse."

In a brief speech after accepting command, McChrystal also emphasized the importance of U.S. forces showing respect for Afghan culture. "The Afghan people are at the center of our mission," he said. "In reality, they are the mission. We must protect them from violence -- whatever its nature. We must respect their religion and traditions."